Uhm, you seem to be reducing your own question to "Does God exist?", because you're assuming that if there's a purpose it must come from the external world.

If you take issue with my reasoning, then I'd rather you debate the points rather than trying to read between the lines because I honestly don't know what the fuck you're talking about. There is noting explicitly theistic, let alone theocentric, about proclaiming that we're a cosmic joke (What kind of answer would that be to the question: "Does God Exist"). The point is that purpose is inevident and thus invalid.